Elixir 1.20 adds gradual type checking with inferred set-theoretic types to flag verified runtime bugs

Elixir v1.20 introduces its first major milestone toward a gradual type system, adding type inference and type checking across existing Elixir programs without requiring annotations. The release can detect dead code and verified bugs that would fail at runtime, while performing strongly on a type-narrowing benchmark.

This brings more static-analysis benefits to a traditionally dynamic language without forcing developers into a full annotation workflow. It reflects a broader trend of gradual typing becoming a practical middle path for mature dynamic ecosystems seeking better reliability at scale.